The Salvia genus (family Lamiaceae) contains about 700 members that can be found in the tropical and temperate zones of the world, with about 300 species distributed in Asia, Europe and Africa and 400 in America (Willis J C (1966) A Dictionary of Flowering Plants and Ferns, 7th Edn., Cambridge, University Press; Briquet J, (1897) Labiatae, In: Die Naturlichen Pflanzenfamilien, Engler and Prantl (Eds.), Vol. IV, 3a, pp. 183-375, Englemann, Leipzig). Numerous varieties of sage species, including varieties of S. sclarea, are known. Clary sage (S. sclarea) is native to the Mediterranean region, has been found growing in the wild, and is cultivated in a number of countries. S. sclarea occurs as an annual (rare), biennial (fairly common) or perennial (fairly common) open-pollinated herbaceous plant that has typical quadrangular stems, opposite leaves and verticillaster inflorescence.
Clary sage is cultivated mainly for the production of essential oil, sclareol and sclareol derivatives. U.S. Pat. No. 3,060,172 describes a process for the isolation of sclareol from clary sage; U.S. Pat. Nos. 5,525,728 and 5,247,100 describe processes for the production of sclareolide from sclareol. Sclareol and sclareol derivatives have been used as major perfume components, in flavoring foodstuffs, in wine making and as components of cigarette flavors. The main areas of commercial production of clary sage are the former Soviet Union, USA, France, China, Bulgaria, Hungary and India. Sage oil and sclareol are produced mainly in flower spikes; about 97 percent of the sclareol is located in the flower spikes, where it is synthesized exclusively in trichomes (the epidermal appendages or hairs) located on the inflorescence organs. The yield of clary sage oil and sclareol is subject to wide fluctuations, depending primarily on weather and soil conditions.
Although conventional plant breeding has played an important role in the improvement of clary sage, the yields of the aforementioned sage related products from such plants are still very low. A method of regenerating Salvia plants would be of assistance in the cultivation of sage and the production of clary sage oil and sclareol, as well as providing tissues and systems for transforming Salvia to provide genetically improved plants. It is therefore desirable to devise methods of regenerating species of Salvia, to provide organogenic lines of Salvia tissues and to reproduce Salvia plants.